MIT engineers have created a new drug delivery technique that opens up the field. If successful, this new approach may redefine how some of our medications are delivered. This novel approach delivers drugs by injecting them as ultra-small crystal suspensions. These crystals then pack into a stable drug “depot” that releases drug over long timescales. The evolution has the potential to minimize the trigger-time injections patients have to endure. These translate into a less painful, much more convenient treatment experience for them.
The researchers demonstrated the feasibility of this approach in rats. They proved that the implantable drug depots were stable and released the medication over an extended duration for three months. Surprisingly, the resulting study demonstrated that at the end, an estimated 85% of the drug remained in the depots. This indicates the possibility for much longer release durations. This development is especially exciting for creating long-acting contraceptive delivery technologies, in addition to other therapeutic uses.
Innovative Approach to Drug Delivery
The novel drug delivery approach was first tested on levonorgestrel, a crystalline hydrophobic molecule. Unlike existing injectable products that rely heavily on precipitating polymers, comprising 23 to 98% of the solution by weight, the MIT approach uses less than 1.6% polymers. This relatively low amount is enough to tune the rate of drug release, all while keeping the formulation injectably viscous.
"By incorporating a very small amount of polymers—less than 1.6% by weight—we can modulate the drug release rate, extending its duration while maintaining injectability. This demonstrates the tunability of our system, which can be engineered to accommodate a broader range of contraceptive needs as well as tailored dosing regimens for other therapeutic applications," said Sanghyun Park, a key researcher in the project.
We begin by delivering the drug solution subcutaneously. The crystals then rapidly self-assemble into a long-lasting depot beneath the skin. This depot serves as a reservoir, allowing the drug to be released gradually and continuously over an extended period.
"The solvent is critical because it allows you to inject the fluid through a small needle, but once in place, the crystals self-assemble into a drug depot," explained Giovanni Traverso, one of the leading engineers behind the innovation.
Long-Lasting Effects and Potential Applications
The ability to increase the drug release time past three months opens many doors to improving health through a number of diverse medical applications. With further development, the research team envisions that these depots could survive for more than a year. This would provide patients with long-term therapeutic benefits.
"We anticipate that the depots could last for more than a year, based on our post-analysis of preclinical data. Follow-up studies are underway to further validate their efficacy beyond this initial proof-of-concept," Park added.
This innovative approach paves the way for new contraceptive formats. These options are simpler to implement and more effective in low- and middle-income countries. The goal is to make sure women have varied opportunities that meet their needs and preferences.
"The overarching goal is to give women access to a lot of different formats for contraception that are easy to administer, compatible with being used in the developing world, and have a range of different timeframes of durations of action," stated Feig, one of the researchers involved in the study.
Future Research and Implications
The results from this preliminary study have been encouraging. Next, we can move on to larger studies to confirm and hone the technique. The researchers are committed to investigating new uses, independent of contraceptives. To better serve patients, they hope to develop doses that fit individual patients for all therapeutic areas.
"In our particular project, we were interested in trying to combine the benefits of long-acting implants with the ease of self-administrable injectables," Feig elaborated.
The potential for this innovative delivery system goes well beyond just contraception. It remains a hopeful technology for patients who need stable drug concentrations for extended durations and want less frequent interactions with the healthcare system.
"We showed that we can have very controlled, sustained delivery, likely for multiple months and even years through a small needle," Giovanni Traverso emphasized.